The present invention relates to a semiconductor device and, in particular, the present invention can be preferably used for a semiconductor device in which a plurality of IC chips are laminated or stacked and which has tamper resistance.
Advance in semiconductor process is accompanied by advance in analysis technology. Owing to the advance in analysis technology, things that have not been able to be seen can be seen and subtle signals that have not been able to be detected can be analyzed, so that it is possible to improve performance and the like. On the other hand, the advance in analysis technology significantly affects development of security technology. There is a so-called side channel attack which analyzes a subtle electromagnetic wave leaked from an LSI (Large Scale Integrated circuit) device and finds out an encryption key. Further, the attack develops to various attacks such as an invasive attack which processes an LSI by FIB (Focused Ion Beam) or the like and reads data flowing through signal wiring in the LSI by micro-probing and a fault injection attack which irradiates an LSI with laser or the like to inject a fault in the LSI and analyzes error data obtained from the fault. Assets possessed by an electronic device include many things such as credit card information, and the degree of importance thereof is increasing, so that it is necessary to improve a mechanism for safeguarding such information, that is, to improve security level (tamper resistance).
Japanese Unexamined Patent Application Publication No. 2007-234001 discloses a semiconductor device which further complicates temporal changes in physical information leaked from an IC (Integrated Circuit) chip by adding a random number generator and an auxiliary arithmetic unit in order to make it difficult to retrieve a secret key from an intercepted power change and electromagnetic irradiation in a power analysis attack and an electromagnetic wave analysis attack.
Japanese Unexamined Patent Application Publication No. 2000-3427 discloses an IC card formed by laminating two IC chips so that their element surfaces face each other in order to prevent information stored in a memory in an integrated circuit from being read by a third party.
Japanese Unexamined Patent Application Publication No. 2006-172122 discloses an IC card in which an IC card function chip that processes security data is laminated at a position other than a lowest layer of a substrate in order to prevent the chip from being broken by a stress.